Weighting of silk



Patented Mar. 4, 1930 UNITED STATES ALBERT FEUBEL, OF KREFELD, GERMANY WEIGHTING F SILK No Drawing. Application filed November 17', 1926, Serial No; 148,996, and in Germany November 28, 1924.

The invention relates to an improved proc-' ess of Weighting silk, especially to a process of impregnating silk fibre with a solution of an aluminum salt and further fixing the aluminum in the form of hydroxide, silicate, phosphate or another insoluble compound, and to silk products so obtained. It is based upon the fact that solutions of basic nitrates of aluminum are particularly Well adapted for this purpose. These solutions are obtained by dissolving fresh-precipitated aluminum hydroxide in less than the equivalent amount of nitric acid. Suitably only about half or less than half of the amount required for the formation of the normal nitratc of aluminum Al(NO 3 is used.

There may also be employed solutions of basic aluminum nitrates containing besides nitric acidbut in a less amount than this acidother acids such as sulfuricor hydrochloric acid provided that the sum of acid available in the solution is substantially smaller than is necessary for saturating all the three valences of aluminum. Such solutions result from dissolving in the least possible amount of nitric acid highly basic sulfates or chlorides of aluminum, insoluble in. water, e. g. the sulfate 2Al O .H- .SO. .6H2O.

The above mentioned solutions are characterized by the fact that the alumina present therein is very readily absorbed by the fibre and will not be removed by washing with water. Just as usual in the well known process of weighting silk with stannic chloride itis necessary to treat further with solutions of compounds'by which aluminum is fixed in a completely insoluble form and the last traces of acid reaction are removed e. g.

with alkali metal silicate or phosphate. The

weighting obtained in this manner is equivalent in effect to the usual weighting by tin salts.

In the same way as for pure silk the new process is of great value for mixed fabrics of natural and artificial silk, where artificial silk means all. the artificial fibres made of cellulose and cellulose derivatives e. g. viscose silk. cuprammonium silk, Chardonnet silk, etc.

The process is illustrated by the following examples but without being limited to this special kind of performance:

1. Silk fabric is impregnated with a basic aluminum nitrate solution having a specific gravity of 1.2 and containing 175 parts of nitric acid to 102 parts of aluminum oxide; the fabric is then freed from the solution by HIGEIHsOf a centrifuge, washed with water and treated at 50 to C. with a solution of sodium silicate (specific gravity 1.01 to 00 1.02). After washing again this process of weighting may be repeated several times, preferably 4 to 5 times but also more. An increase in weight of about 15 per cent is effected by each subsequent treatment with the solutions of basic nitrate and sodium silicate.

2. A mixed fabric of natural and viscose silk is impregnated with a solution of the specific gravity of 1.22 containing in one liter 110 parts of aluminum oxide, 160 parts of nitric acid and 50 parts of sulfuric acid and further treated as described in the preceding example.

I claim:

1. In processesof weighting silk by means of salts of heavy metals, the step which consists in treating unweighted silk with a solution of a basic aluminum compound containing nitrate radicles.

2. In processes of weighting silk by means of salts of heavy metals, the step whicl1 consists in treating the unweighted silk with a solution of a basic aluminum nitrate.

3. In processes of weighting silk by means of salts of heavy metals, the steps which consist in treating unweighted silk with a solution of a basic aluminum compound containing nitrate radicles, subjecting the resulting treated silk to treatment with a solution of a compound capable of fixing aluminum in completely insoluble form.

4. In processes of weighting silk by means of salts of heavy metals, the steps which consist in treating unweighted silk with a solution of a basic aluminum compound eontaining nitrate radicles, and subjecting the resulting treated silk to treatment with a solution of an alkaline reacting salt of an alkali metal.

5. In processes of weighting silk by means of salts of heavy metals, the steps which consist in treating unweighted silk with a solution of a basic aluminum compound containing nitrate radicles, and subjecting the resulting treated silk to treatment with a solution of sodium silicate.

6. In processes of weighting silk by means of salts of heavy metals, the steps which consist in treating the unweighted silk with a solution of a basic aluminum nitrate and subjecting the resulting treated silk to treatment ing the unweighted material with a solution of a basic aluminum nitrate and subjecting the resulting treated material to treatment with a solution of sodium silicate.

In testimony whereof I have hereunto set in hand.

7 ALBERT FEUBEL.

with a solution of a compound capable of fix solution of a basic aluminum nitrate, and subj ecting the resulting treated silk to treatment with a solution of sodium silicate.

. 9. In processes of weighting material of natural and artificial silk by means of salts of heavy metals, the step which consists inrtreat ingthe unweighted material with a solution of a basic aluminum compound containing nitrate radicles.

10. In processes of weighting material of natural and artificial silk by means of salts of heavy metals, the step which consists in treating the unweighted material with. a solution of abasic aluminum nitrate.

-11.-In processes of weighting material of natural and artificial silk by means of salts of heavy metals, the steps which consists in treating the unweighted material with a solution of a basic aluminum compound containing nitrate radicles, and subjecting the resulting treated material to treatment with a solution of a compound capable of fixing aluminum in completely insoluble form;

12. In processes of weighting material of natural and artificial silk by means of salts of heavy metals, the steps which consist in treating the unweighted material with a solution of a basic aluminum compound containing ni trate radicles, and subjecting the resulting treated material to treatment with a solution I of an alkaline reacting salt of an alkali metal. 13. In processes of weighting material of natural and artificial silk by means of salts of heavy metals, the steps which consist .in treating the unweighted material with a solution of a basic aluminum compound containing nitrate radicles,f'and subjecting the resulting treated material to treatment with a solution of sodium silicate.

14. In processes of weighting material of natural and artificial silk by means of salts of heavy metals, the steps which consist in. treat- 

